Schweitzer Engineering Laboratories, Inc. (SEL) designs, manufactures, and supports products and services ranging from generator and transmission protection to distribution automation and control systems.

The company serves a variety of industries, including utilities, pulp and paper, transportation, water and wastewater, education, healthcare, government, mission-critical facilities, and oil, gas, and petrochemical operations.

SEL was founded in Pullman, Washington in 1982 when Dr. Edmund O. Schweitzer III invented and marketed the first all-digital protective relay.

With International integration centers in San Luis Potosí, Mexico (2003), Campinas, Brazil; Bogota, Colombia; and Khobar, Dammam Saudi Arabia (May 2017).

The company's other published works include: Line Current Differential Protection: A Collection of Technical Papers Representing Modern Solutions, edited by Héctor J. Altuve Ferrer, Bogdan Kasztenny, and Normann Fischer; Analyzing and Applying Current Transformers, by Stanley Zocholl; and AC Motor Protection, by Stanley Zocholl.